Methods and Apparatus for Providing Soft and Blind Combining for PUSCH Acknowledgement (ACK) Processing

ABSTRACT

Methods and apparatus for providing soft and blind combining for PUSCH acknowledgement (ACK) processing. In an exemplary embodiment, a method includes soft-combining acknowledgement (ACK) bits received from a UE that are contained in a received sub-frame of symbols. The ACK bits are soft-combined using a plurality of scrambling sequences to generate a plurality of hypothetical soft-combined ACK bit streams. The method also includes receiving a parameter that identifies a selected scrambling sequence to be used. The method also includes decoding a selected hypothetical soft-combined ACK bit stream to generate a decoded ACK value, wherein the selected hypothetical soft-combined ACK bit stream is selected from the plurality of hypothetical soft-combined ACK bit streams based on the parameter.

CLAIM TO PRIORITY

This application claims the benefit of priority based upon U.S.Provisional Patent Application having Application No. 62/267,221, filedon Dec. 14, 2015, and entitled “Method and Apparatus for Providing Softand Blind Combining Techniques for PUSCH Baseband Processing,” which ishereby incorporated herein by reference in its entirety.

FIELD

The exemplary embodiments of the present invention relate totelecommunications networks. More specifically, the exemplaryembodiments of the present invention relate to receiving and processingdata streams via a wireless communication network.

BACKGROUND

There is a rapidly growing trend toward mobile and remote data accessover high-speed communication networks, such as provided by 3G or 4Gcellular services. For example, using these services, users now rely ontheir smartphones for texting, access to email, banking, and socialmedia, and for sending and receiving pictures and video.

Typically, wireless network performance depends in part on the qualityof the transmission channel. For example, if the channel conditions aregood, the network may perform with higher speed and capacity than whenthe channel conditions are poor. To obtain the best network performance,wireless networks may rely on user devices (e.g., user equipment “UE”)to report control information back to the network. The controlinformation includes parameters indicating the channel conditions and/ortransmission parameters. One way user devices report control informationback to the network is through a physical uplink shared channel (PUSCH).The network receives the control information over this shared channeland uses the received parameters to adjust data transmissions foroptimum performance based on the network conditions indicated by thereceived parameters.

Acknowledgement information is also transmitted through the PUSCH. Forexample, after a user device receives a transmission from a networkserver, it generates an acknowledgement (ACK) that indicates whether ornot the transmission was properly received. The ACK is then transmittedback to the network server through the PUSCH. The server can determinefrom the received ACK whether the transmission was properly received,and initiate a retransmission if necessary. In a time division duplex(TDD) communication system, the user device generates encoded ACK blocksthat are scrambled with a scrambling sequence before transmission overthe PUSCH for a TDD ACK bundling scenario. Typically, the scramblingsequence for TDD ACK bundling is selected from four or more possiblescrambling sequences.

When the ACK information on the PUSCH is received at the network server,it is processed to obtain the actual ACK values. For example, theprocessing may include descrambling, soft-combining, and decoding of thereceived ACK information. In order to do this, conventional systemsfirst determine the correct scrambling sequence for TDD ACK bundlingthat was used to scramble the ACK information. Once the exact scramblingsequence is determined, the process to recover the ACK information canbe performed using that scrambling sequence to descramble the receivedinformation.

However, in conventional systems, additional parameters may need to beacquired and/or data processing may need to be performed before theexact scrambling sequence can be determined. Thus, conventional systemshave to wait to perform these additional functions to determine theexact scrambling sequence before performing the operations needed torecover the ACK information, which may result in reduced networkperformance.

Therefore, it is desirable to have a mechanism that efficiently recoversreceived acknowledgement information and overcomes the problemsassociated with conventional systems.

SUMMARY

In various exemplary embodiments, methods and apparatus for providingsoft and blind combining for PUSCH ACK processing are disclosed. Forexample, in a TDD communication system, user equipment generates encodedACK blocks that are scrambled with a selected scrambling sequence(selected from multiple available scrambling sequences) beforetransmission over the PUSCH to a network server for the TDD ACK bundlingcase. In various exemplary embodiments, an ACK hypothesis generatoroperates at the network server to generate a hypothetical soft-combinedACK bit stream for each possible scrambling sequence. A decoder receivesa calculated parameter that indicates the exact scrambling sequence andthis indicator is used to select and decode the correct hypothetical ACKbit stream to generate a decoded ACK value. Generating a hypotheticalsoft-combined ACK bit stream for each possible scrambling sequence whilethe network parameter is being calculated speeds up ACK processing andresults in improved network performance.

In an exemplary embodiment, a method is provided that includessoft-combining acknowledgement (ACK) bits received from a UE that arecontained in a received sub-frame of symbols. The ACK bits aresoft-combined using a plurality of scrambling sequences to generate aplurality of hypothetical soft-combined ACK bit streams. The method alsoincludes receiving a parameter that identifies a selected scramblingsequence to be used. The method also includes decoding a selectedhypothetical soft-combined ACK bit stream to generate a decoded ACKvalue, wherein the selected hypothetical soft-combined ACK bit stream isselected from the plurality of hypothetical soft-combined ACK bitstreams based on the parameter.

In another exemplary embodiment, an apparatus is provided that includesa soft-combiner that soft-combines acknowledgement (ACK) bits receivedfrom a UE that are contained in a received sub-frame of symbols. The ACKbits are soft-combined using a plurality of scrambling sequences togenerate a plurality of hypothetical soft-combined ACK bit streams. Theapparatus also includes a decoder that receives a parameter thatidentifies a selected scrambling sequence to be used and decodes aselected hypothetical soft-combined ACK bit stream to generate a decodedACK value. The selected hypothetical soft-combined ACK bit stream isselected from the plurality of hypothetical soft-combined ACK bitstreams based on the parameter.

In another exemplary embodiment, an apparatus is provided that includesmeans for soft-combining acknowledgement (ACK) bits received from a UEthat are contained in a received sub-frame of symbols. The ACK bits aresoft-combined using a plurality of scrambling sequences to generate aplurality of hypothetical soft-combined ACK bit streams. The apparatusalso includes means for receiving a parameter that identifies a selectedscrambling sequence to be used. The apparatus also includes means fordecoding a selected hypothetical soft-combined ACK bit stream togenerate a decoded ACK value. The selected hypothetical soft-combinedACK bit stream is selected from the plurality of hypotheticalsoft-combined ACK bit streams based on the parameter.

Additional features and benefits of the exemplary embodiments of thepresent invention will become apparent from the detailed description,figures and claims set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

The exemplary aspects of the present invention will be understood morefully from the detailed description given below and from theaccompanying drawings of various embodiments of the invention, which,however, should not be taken to limit the invention to the specificembodiments, but are for explanation and understanding only.

FIG. 1 shows a communication network comprising a transceiver having anexemplary embodiment of an ACK hypothesis generator configured toefficiently receive and process acknowledgement information from userequipment;

FIG. 2 shows a diagram illustrating an exemplary uplink transmissionfrom a UE through a communication network to a receiver having anexemplary embodiment of the hypothetical ACK generator shown in FIG. 1;

FIG. 3 shows an exemplary Table that illustrates exemplary encoding of a1-bit acknowledgment parameter;

FIG. 4 shows an exemplary Table that illustrates exemplary encoding of a2-bit acknowledgment parameter;

FIG. 5 shows an exemplary Table that illustrates exemplary scramblingsequences used for ACK bundling;

FIG. 6 shows an exemplary embodiment of an exemplary process forpreparing ACK bits to be included in a transport block;

FIG. 7 shows an exemplary subframe that includes resource elementscontaining acknowledgement LLR bits transmitted from a UE;

FIGS. 8A-D show exemplary embodiments of 1-bit and 2-bit mappings ofencoded acknowledgement information and associated scrambling sequences;

FIG. 9 shows a detailed exemplary embodiment of an ACK hypothesisgenerator;

FIG. 10 shows exemplary hypothetical ACK values generated by anexemplary embodiment of an ACK hypothesis generator;

FIG. 11 shows a detailed exemplary embodiment of an ACK soft combinerthat generates hypothetical acknowledgement values;

FIG. 12 shows a detailed exemplary embodiment of a decoder that decodesa selected hypothetical soft-combined ACK bit stream;

FIG. 13 shows an exemplary method for efficiently generatinghypothetical soft-combined ACK bits streams to decode an ACK value inaccordance with an exemplary embodiment of the present invention; and

FIG. 14 shows an exemplary embodiment of an apparatus that efficientlygenerates hypothetical soft-combined ACK bits streams to decode an ACKvalue in accordance with an exemplary embodiment of the presentinvention.

DETAILED DESCRIPTION

Aspects of the present invention are described herein in the context ofmethods and/or apparatus for processing control information relating towireless data.

The purpose of the following detailed description is to provide anunderstanding of one or more embodiments of the present invention. Thoseof ordinary skills in the art will realize that the following detaileddescription is illustrative only and is not intended to be in any waylimiting. Other embodiments will readily suggest themselves to suchskilled persons having the benefit of this disclosure and/ordescription.

In the interest of clarity, not all of the routine features of theimplementations described herein are shown and described. It will, ofcourse, be understood that in the development of any such actualimplementation, numerous implementation-specific decisions may be madein order to achieve the developer's specific goals, such as compliancewith application and/or business related constraints, and that thesespecific goals will vary from one implementation to another and from onedeveloper to another. Moreover, it will be understood that such adevelopment effort might be complex and time-consuming, but wouldnevertheless be a routine undertaking of engineering for those ofordinary skills in the art having the benefit of embodiments of thisdisclosure.

Various embodiments of the present invention illustrated in the drawingsmay not be drawn to scale. Rather, the dimensions of the variousfeatures may be expanded or reduced for clarity. In addition, some ofthe drawings may be simplified for clarity. Thus, the drawings may notdepict all of the components of a given apparatus (e.g., device) ormethod. The same reference indicators will be used throughout thedrawings and the following detailed description to refer to the same orlike parts.

The term “system” or “device” is used generically herein to describe anynumber of components, elements, sub-systems, devices, packet switchelements, packet switches, access switches, routers, networks, modems,base stations, eNB (eNodeB), computer and/or communication devices ormechanisms, or combinations of components thereof. The term “computer”includes a processor, memory, and buses capable of executing instructionwherein the computer refers to one or a cluster of computers, personalcomputers, workstations, mainframes, or combinations of computersthereof.

One aspect of the present invention discloses a device capable ofhypothesizing possible ACK information in a wireless communicationsnetwork. The process includes obtaining a subframe of symbols containinguplink ACK information via a physical uplink shared channel (PUSCH).Generating hypothetical soft-combined ACK bit streams for each possiblescrambling sequence while a network parameter is calculated. Aftergenerating the hypothetical soft-combined ACK bit streams, they arestored in a local memory. In one embodiment, the calculated networkparameter is used to select a particular hypothetical soft-combined ACKbit stream that is decoded to generate a decoded ACK value for output.

FIG. 1 shows a communication network 100 comprising a transceiver 116having an exemplary embodiment of an ACK hypothesis generator (AHG) 118configured to efficiently receive and process ACK information from userequipment. The network 100 may also be referred to as a third generation(3G), 4G, LTE, or combination of 3G and 4G cellular networkconfiguration.

The communication network 100 includes a server 114 that includes thetransceiver 116. The transceiver 116 has a transmitter portion 128 and areceiver portion 130. The server 114 is configured to communicate with aserving gateway (S-GW) 108 that is further configured to communicatewith cell site 102 and the Internet 112. The cell site 102 includesradio towers 110 and associated base stations (not shown).

User equipment (UE) 104 is in communication with base station 110B usingchannel A 120 and user equipment 106 is in communication with basestation 110B using channel B 122. For example, the UEs can be cellularphones, handheld devices, tablet computers or iPad® devices. It shouldbe noted that the underlying concepts of the exemplary embodiments ofthe present invention would not change if one or more blocks (ordevices) were added or removed from the communication network 100.

The receiver portion 130 includes receiver processing hardware (RPH)132. In an exemplary embodiment, the RPH 132 includes the ACK hypothesisgenerator 118, which is used to facilitate efficient recovery of the ACKinformation received from UEs. To improve efficiency and/or speed fordecoding ACK information in uplink transmissions received through aPUSCH via the network 100, one aspect of the present invention operatesto soft-combine ACK information for all possible TDD ACK scramblingsequences or multiple scrambling sequences while at the same time anetwork parameter is calculated. The network parameter identifies thecorrect scrambling sequence that was used to scramble the received ACKinformation. Once the network parameter is calculated, the correcthypothetical soft-combined ACK bit stream can be selected and decoded togenerate the decoded ACK value.

One advantage of using the AHG 118 is that the receiver portion 130 isable to recover the ACK information from the received subframe quicklyto enhance overall efficiency of the receiver and the communicationnetwork 100.

FIG. 2 shows a diagram illustrating an exemplary uplink transmissionfrom a UE through a communication network to a receiver having anexemplary embodiment of the ACK hypothesis generator 118. For example,the uplink transmission from the UE 104 flows through the communicationnetwork 100 to the receiver portion 130 of the transceiver 116. It willbe assumed that the UE 104 generates the control information 126 andtransmits this control information using antenna 222 to the tower 110B,as illustrated by transmission 120. In an exemplary embodiment, thecontrol information 126 is transmitted over a PUSCH to the server 114.The uplink transmission flows to the receiver portion 130 of thetransceiver 116. At the receiver portion 130, the uplink transmission isreceived at an uplink front end (ULFE) 212. After receiving the uplinktransmission, the ULFE 212 passes received information to receiverprocessing hardware (RPH) 132.

The RPH 132, in one exemplary embodiment, includes MMSE 202, IDFT 204,demapper 206, descrambler 208 and combiner 210. In an exemplaryembodiment, the RPH 132 includes configuration parameters (CF) 224 andthe signal combiner 210 includes an exemplary embodiment of the AHG 118.The RPH 132 is configured to process information received by the ULFE212 and the result of such processing is output to a decoder (notshown). The information includes user data and control information. Thecontrol information is used to facilitate information transmission overa wireless communication network, such as the network 100.

The MMSE 202, in one example, includes an equalizer with serialinterference cancellation (“SIC”) capability. The MMSE 202 generatesestimated values using a function of mean-square-error or equalizationof received signals or bit stream(s) during the signal processing phase.MMSE 202 also provides functionalities to equalize multiple streams ofdata received simultaneously over the air. For instance, the number ofbit streams such as one (1) to eight (8) streams can arrivesimultaneously.

The IDFT 204 converts symbols or samples between frequency domains.After conversion, the IDFT 204 may store the symbols or samples in astorage matrix (not shown). Depending on the application, the IDFT 204passes the symbols to the next logic block, which is the demapper 206.The storage matrix is a local storage memory which can reside in theIDFT 204, the demapper 206, or at an independent storage location.

The Demapper 206 operates to demap or ascertain soft bit informationassociated with received symbol(s) or bit stream(s). For example,demapper 206 employs a soft demapping principle, which is based oncomputing the log-likelihood ratio (LLR) of a bit that quantifies thelevel of certainty as to whether it is a logical zero or one. To reducenoise and interference, the demapper 206 is also capable of discardingone or more unused constellation points relating to the frequency of thebit stream from the constellation map.

The descrambler 208 is configured to generate and descramble a sequenceof bits or a stream of bits. For example, after generating a sequence inaccordance with the input value, the descrambler determines whethersequence modification is needed for certain categories of controlinformation. The stream of bits or sequence is subsequently descrambledto produce a set of descrambled soft bits.

The combiner 210 provides a combining function that combines LLR bits toform bit streams to be decoded. In an exemplary embodiment, the combiner210 includes an exemplary embodiment of the ACK hypothesis generator118. As disclosed in greater detail below, the AHG 118 operates toimprove the speed and efficiency of the combiner 210 by providing forconcurrent or simultaneous soft-combining of hypothetical ACKinformation while a network parameter is calculated. Once the networkparameter is calculated, the correct hypothetical ACK bit stream can beselected and operations performed to recover a decoded ACK value fromeach UE in a faster and more efficient process. The resulting ACK valueis passed to downstream processing.

The RPH 132 also includes CF 224 that provides configuration parametersto the various functions blocks of the RPH 132. Although the CF 224 isshown only in communication with the combiner 210, in various exemplaryembodiment, the CF 224 communicates with other components of the RPH 132to provide configuration parameters as necessary.

FIG. 3 shows an exemplary Table 300 that illustrates exemplary encodingof a 1-bit acknowledgment parameter. For example, in an exemplaryembodiment, the Table 300 is used by user equipment to encode 1-bitacknowledgement information.

FIG. 4 shows an exemplary Table 400 that illustrates exemplary encodingof a 2-bit acknowledgment parameter. For example, in an exemplaryembodiment, the Table 400 is used by user equipment to encode 2-bitacknowledgement information. Table 300 and 400 show ACK encoding foreach modulation order Q_(m).

The ACK parameter is encoded as binary 1 and means that a transmissionwas successfully received. A NACK parameter is encoded as binary 0 andmeans that a transmission was not successfully received. A third bit (O₂^(ACK)) is obtained from 2-bit information for the 2-bit ACK case asfollows (O₂ ^(ACK)=(O₀ ^(ACK)+O₁ ^(ACK))mod 2).

In the Table 300 and the Table 400, the “y” and “x” bits are placeholders and are used in the scrambling stage after the channelinterleaver for repetition and for making sure that ACK information iscarried by the highest power modulation symbols in the constellation.

Encoded ACK bits are subsequently repeated (rate matched) via blockconcatenation until the total number of bits reaches(Q_(ACK)=Q′_(ACK)*Q_(m)), where Q′_(ACK) is the number of ACK symbolsper layer and Q_(m) is the modulation order. In the case of ACKbundling, there is an additional scrambling stage prior to obtaining thefinal bit sequence to be placed in the transport block.

FIG. 5 shows an exemplary Table 500 that illustrates exemplaryscrambling sequences used for ACK bundling. Selection of the scramblingsequence (i) to be used is controlled by a parameter called N_(bundled).Thus, based on the value of i the corresponding scrambling sequence isused to scramble rate matched ACK bits to obtain the final ACK bitsequence to be place in the transport block.

FIG. 6 shows an exemplary embodiment of a process 600 for preparing ACKbits to be included in a transport block. For example, in a firstprocess, 1-bit or 2-bit ACK encoding is performed as shown at block 602.In a second process, rate matching is performed by a block concatenationprocess 604. In a third process that is only used for the case of ACKbundling, a scrambling process 606 is performed using the appropriatescrambling sequence that is determined by the N_(bundled) parameter.

In an exemplary embodiment, the process 600 is reversed at the devicereceiving the transmit block in order to recover O₀ ^(ACK), O₁ ^(ACK),and O₂ ^(ACK) successfully. Subcarriers of the relevant symbols of thereceived PUSCH subframe needs to be soft-combined as a part of thederate-matching process. This traditionally requires the exact knowledgeof the scrambling sequence given by the index i of Table 500.

FIG. 7 shows an exemplary subframe 700 that includes resource elementscontaining acknowledgement LLR bits transmitted from a UE. For example,the subframe 700 comprises symbols 702 and resource elements (RE) 704.The bits indicated at 706 represent the ACK LLR bits received in thesubframe 700 that are transmitted from a UE, such as UE 104.

The subframe 700 comprises twelve symbols 702 for each row of resourceelements (RE) 704. In an exemplary embodiment, each symbol comprisesbits representing two values. For example, as illustrated in thesubframe 700, the ACK LLR bits appear in symbols 2 and 9 of resourceelements 7-11 and symbols 3 and 8 of resource elements 8-11. It shouldbe noted that the subframe 700 in FIG. 7 is exemplary and that otherconfigurations with different numbers of REs, bits, and bit arrangementsfor the ACK information are possible.

FIGS. 8A-D show exemplary embodiments of 1-bit and 2-bit mappings ofencoded acknowledgement information and associated scrambling sequencemappings. FIG. 8A shows an exemplary mapping of 1-bit ACK bits in theappropriate symbols and REs of the subframe 700. FIG. 8B shows anexemplary scrambling sequence mapping that can be used to descramble the1-bit ACK mapping shown in FIG. 8A. FIG. 8C shows an exemplary mappingof 2-bit ACK bits in the appropriate symbols and REs of the subframe700. FIG. 8D shows an exemplary scrabbling sequence mapping that can beused to descramble the 2-bit ACK mapping shown in FIG. 8C.

FIG. 9 shows a detailed exemplary embodiment of an ACK hypothesisgenerator 900. For example, the AHG 900 is suitable for use as the AHG118 shown in FIGS. 1-2.

The AHG 900 comprises ACK soft-combiner 902, memory 904, and ACK decoder906. Although shown separately, the components of FIG. 9 also can becombined in any combination and/or arrangement within the scope of theembodiments. It should be noted that the underlying concept of theexemplary embodiments of the present invention would not change if oneor more components were added or removed from the AHG 900 shown in FIG.9.

The ACK hypothesis generator 900 operates to receive configurationparameter 906 and symbols from a received uplink subframe 916. Thesoft-combiner 902 operates to descramble and soft-combine ACK LLR bitsin the received subframe according to the 1-bit mappings, 2-bitmappings, and corresponding descrambling sequence mappings shown above.In an exemplary embodiment, the ACK soft combiner 902 also receivesconfiguration parameters 908 from the CF 224. In an exemplaryembodiment, these parameters provide the possible TDD ACK bundlingscrambling sequences (e.g., as shown in Table 500) that may be used byany particular UE. These parameters also may indicate how the ACK LLRbits in the REs are to be soft-combined. For example, the REs containingACK bits may not be contiguous in the subframe and the parameters fromthe CF 224 may indicate the location of the REs to be used in the softcombining process. Thus, the ACK soft-combiner 902 carries out the ACKdescrambling and soft-combining blindly for all scrambling sequences anddoesn't require explicit information regarding the specific TDD ACKbundling scrambling sequence used by the UE.

The soft-combiner 902 generates four (4) hypothetical soft-combined ACKbit streams 910 corresponding to the four possible scrambling sequencesand stores these ACK bit streams 910 into the memory 904. Thus,soft-combining is performed for all (or a plurality) of the possiblescrambling sequences that may be used at the UE that transmitted thesubframe.

While the hypothetical ACK bit streams are being generated, the networkparameter I (that identifies the exact scrambling sequence) is computedby upper layers of the device that receives the subframe. The networkparameter I is input to the ACK decoder 906.

The ACK decoder 906 receives the I parameter and uses this value toselect the exact scrambling sequence and the corresponding hypotheticalACK bit stream to decode to obtain the correct ACK value. The ACKdecoder 906 then sends a select request 914 to the memory 904 toretrieve the correct (selected) hypothetical ACK bit stream 912. Oncethe correct hypothetical ACK bit stream 912 is retrieve, the ACK decoder906 decodes this bit stream to determine a decoded ACK value 920. Forthe case of a 1-bit ACK, the hypothetical ACK bit stream is the decodedACK value 920 and is then output. For the case of a 2-bit ACK, thehypothetical ACK bit stream is decoded as described above to obtain theACK value 920.

FIG. 10 shows exemplary hypothetical ACK values generated by the ACKhypothesis generator 902. In an exemplary embodiment, 4 ACK hypothesisare produced each corresponding to one row of Table 500. The generatedoutput for both scenarios, namely the 1-bit and 2-bit cases are alsoshown in FIG. 10. For example, the 1-bit hypothesis values are shown at1002 and the 2-bit hypothesis values are shown at 1004.

FIG. 11 shows a detailed exemplary embodiment of an ACK soft combiner1100 that generates hypothetical acknowledgement values. For example,the ACK soft combiner 1100 is suitable for use as the ACK soft-combiner902 shown in FIG. 9. The ACK soft combiner 1100 comprises processor1102, memory 1104, parameter input register 1106, subframe inputregister 1110, and bit stream output register 1108, all communicatingover bus 1112.

The parameter input register 1106 receives various configurationparameters and passes the received information to the processor 1102.For example, the configuration parameters include the possiblescrambling sequences as shown in Table 500. The processor 1102 uses thereceived configuration parameters to determine whether the ACK encodingis 1-bit or 2-bits and the possible corresponding scrambling sequences.The subframe input register 1110 operates to receive symbols of areceived subframe. For example, the symbols of the subframe 700 areinput to the subframe input interface 1110.

The processor 1102 generates scrambling sequence mappings for each ofthe possible scrambling sequences. For example, for each of the 1-bitscrambling sequences the processor generates a scrambling sequencemapping table similar to the table in FIG. 8B and for each 2-bitscrambling sequence the processor 1102 generates a scrambling sequencemapping table similar to table in FIG. 8D.

The processor 1102 then applies the scrambling sequence mappings to thesymbols in the received subframe to unscramble the data and thensoft-combines the results to generate 4 hypothetical soft-combined ACKbit streams. For example, each of the soft-combined ACK bit streamscorresponds to a particular scrambling sequence. The processor 1102 thenoutputs the 4 hypothetical soft-combined ACK bit streams from the bitstream output register 1108.

Thus, the ACK soft combiner 1100 operates to receive variousconfiguration parameters (e.g., possible scrambling sequences) at theinput register 1106, receive symbols of a subframe at input interface1110, and generates the 4 hypothetical soft-combined ACK bit streamsthat are output from the bit stream output register 1108.

FIG. 12 shows a detailed exemplary embodiment of a decoder 1200 thatdecodes a selected hypothetical soft-combined ACK bit stream. Forexample, the decoder 1200 is suitable for use as the decoder 906 shownin FIG. 9. The decoder 1200 comprises processor 1202, memory 1204,parameter I input interface 1210, hypothetical soft-combined ACK bitstream interface 1206, and ACK output register 1208, all communicatingover bus 1212.

The parameter I input interface 1210 receives the parameter I that iscalculated by upper layers at the device and that indicates the correctscrambling sequence to be used to descramble and soft-combined the ACKLLR bits. The processor 1102 uses the received parameter I to determinewhich of the hypothetical ACK bit streams to decode. The processor 1202controls the hypothetical ACK input interface 1206 to output a bitstream select signal 1214 that is input to the memory 904 to obtain theselected hypothetical soft-combined ACK bit stream. The processor 1202then decodes this bit stream to generate a decoded ACK value that isoutput from the ACK output register 1208.

In an exemplary embodiment, if the selected hypothetical soft-combinedACK bit stream represents a 1-bit ACK, the processor 1202 passes thisvalue directly to the ACK output register 1208. If the selectedhypothetical soft-combined ACK bit stream represents a 2-bit ACK, theprocessor 1202 decodes this bit stream as describe above to determinethe decoded ACK value to be output from the output register 1208. Forexample, in an exemplary embodiment, the soft-combined bit stream isdecoded according to (O₂ ^(ACK)=(O₀ ^(ACK)+O₁ ^(ACK))mod 2) to determinethe decoded ACK value to be output.

Thus, the decoder 1200 operates to receive a calculated parameter I anduses this parameter to select the correct hypothetical soft-combined ACKbit stream stored in the memory 904. This bit stream is then decoded togenerate a decoded ACK value that is output from the register 1208.

FIG. 13 shows an exemplary method for determining an ACK value bygenerating hypothetical soft-combined ACK bits streams using anexemplary embodiment of a ACK hypothesis generator in accordance with anexemplary embodiment of the present invention.

At block 1302, an uplink transmission is received from one or more UEs.For example, uplink transmissions are received at the server 114 fromthe devices 104, 106 shown in FIG. 1. The uplink transmission includesACK information, such as ACK information 126, 124 received at the server114 in a PUSCH.

At block 1304, a subframe of symbols is recovered from the uplinktransmission. For example, the RHP 132 shown in FIG. 2 receives theuplink transmissions at the ULFE 212 and processes the transmissionsusing the MMSE 202, IDFT 204, demapper 206 and descrambler 208 togenerate the subframe of received symbols that are input to combiner210. For example, the subframe 700 having ACK LLR bits 706 is generated.

At block 1306, ACK descrambling and soft-combining is performed. Forexample, the soft-combiner 1100 performs descrambling and soft-combiningof the ACK LLR bits in the subframe to generate a separate hypotheticalsoft-combined ACK bit stream for each possible scrambling sequence asdescribed above.

At block 1308, the hypothetical soft-combined ACK bit streams are storedin a memory. For example, hypothetical soft-combined ACK bit streams arestored the in the memory 904.

At block 1310, a parameter I is received from upper layers at thedevice. For example, the upper layer compute or determine the Iparameter which indicates the correct scrambling sequence to be used todescramble the ACK LLR bits. In an exemplary embodiment, the I parameteris received at the ACK decoder 906.

At block 1312, based on the received I parameter, the correcthypothetical soft-combined ACK bit stream is decoded to form a decodedACK value. For example, the ACK decoder 906 receives the I parameter 918and uses this value to retrieve a particular hypothetical soft-combinedACK bit stream from the memory 904 and decodes this bit stream togenerate the decoded ACK value.

At block 1314, the decoded ACK value is output. For example, the decoder906 outputs the decoded ACK value 920 to downstream processes.

Thus, the method 1300 operates to efficiently determine an ACK value bygenerating hypothetical soft-combined ACK bits streams using anexemplary embodiment of a ACK hypothesis generator in accordance with anexemplary embodiment of the present invention.

FIG. 14 shows an exemplary embodiment of an apparatus 1400 thatefficiently determines an ACK value by generating hypotheticalsoft-combined ACK bits streams in accordance with an exemplaryembodiment of the present invention.

The apparatus 1400 includes means 1402 for soft-combiningacknowledgement (ACK) bits received from a UE that are contained in areceived sub-frame of symbols. The ACK bits are soft-combined using aplurality of scrambling sequences to generate a plurality ofhypothetical soft-combined ACK bit streams, which in an exemplaryembodiment comprises the soft-combiner 902.

The apparatus 1400 also includes means 1404 for receiving a parameterthat identifies a selected scrambling sequence to be used, which in anexemplary embodiment comprises the decoder 906.

The apparatus 1400 also includes means 1406 for decoding a selectedhypothetical soft-combined ACK bit stream to generate a decoded ACKvalue, wherein the selected hypothetical soft-combined ACK bit stream isselected from the plurality of hypothetical soft-combined ACK bitstreams based on the parameter, which in an exemplary embodimentcomprises the decoder 906.

Thus, the apparatus 1400 operates to efficiently determines an ACK valueby generating hypothetical soft-combined ACK bits streams in accordancewith an exemplary embodiment of the present invention.

The exemplary aspect of the present invention includes variousprocessing steps as described above. The steps may be embodied inmachine or computer executable instructions. The instructions can beused to cause special purpose system, which is programmed with theinstructions, to perform the steps of the exemplary embodiment of thepresent invention. Alternatively, the steps of the exemplary embodimentof the present invention may be performed by specific hardwarecomponents that contain hard-wired logic for performing the steps, or byany combination of programmed computer components and custom hardwarecomponents.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art that,based upon the teachings herein, changes and modifications may be madewithout departing from these exemplary embodiments and their broaderaspects. Therefore, the appended claims are intended to encompass withintheir scope all such changes and modifications as are within the truespirit and scope of these exemplary embodiments of the presentinvention.

What is claimed is:
 1. A method, comprising: soft-combiningacknowledgement (ACK) bits received from a UE that are contained in areceived sub-frame of symbols, wherein the ACK bits are soft-combinedusing a plurality of scrambling sequences to generate a plurality ofhypothetical soft-combined ACK bit streams; receiving a parameter thatidentifies a selected scrambling sequence to be used; and decoding aselected hypothetical soft-combined ACK bit stream to generate a decodedACK value, wherein the selected hypothetical soft-combined ACK bitstream is selected from the plurality of hypothetical soft-combined ACKbit streams based on the parameter.
 2. The method of claim 1, whereinthe decoding comprises: determining if the selected hypotheticalsoft-combined ACK bit stream represents a 1-bit ACK; and outputting theselected hypothetical soft-combined ACK bit stream as the decoded ACKvalue, if it is determined that the selected hypothetical soft-combinedACK bit stream represents a 1-bit ACK.
 3. The method of claim 1, whereinthe decoding comprises: determining if the selected hypotheticalsoft-combined ACK bit stream represents a 2-bit ACK; decoding theselected hypothetical soft-combined ACK bit stream to determine thedecoded ACK value, if it is determined that the selected hypotheticalsoft-combined ACK bit stream represents a 2-bit ACK; and outputting thedecoded ACK value.
 4. The method of claim 3, wherein the decodingcomprises decoding a two bit ACK value according to an equationexpressed as (O₂ ^(ACK)=(O₀ ^(ACK)+O₁ ^(ACK))mod 2).
 5. The method ofclaim 1, further comprising storing the plurality of hypotheticalsoft-combined ACK bit streams in a memory.
 6. The method of claim 1,further comprising receiving the subframe of symbols in an uplinktransmission from the UE.
 7. The method of claim 6, wherein the uplinktransmission comprises an LTE uplink transmission.
 8. The method ofclaim 6, wherein the uplink transmission is received over a physicaluplink shared channel (“PUSCH”).
 9. The method of claim 1, furthercomprising performing the method for a plurality of UE.
 10. Anapparatus, comprising: a soft-combiner that soft-combinesacknowledgement (ACK) bits received from a UE that are contained in areceived sub-frame of symbols, wherein the ACK bits are soft-combinedusing a plurality of scrambling sequences to generate a plurality ofhypothetical soft-combined ACK bit streams; and a decoder that receivesa parameter that identifies a selected scrambling sequence to be usedand decodes a selected hypothetical soft-combined ACK bit stream togenerate a decoded ACK value, wherein the selected hypotheticalsoft-combined ACK bit stream is selected from the plurality ofhypothetical soft-combined ACK bit streams based on the parameter. 11.The apparatus of claim 10, wherein the decoder determines if theselected hypothetical soft-combined ACK bit stream represents a 1-bitACK, and outputs the selected hypothetical soft-combined ACK bit streamas the decoded ACK value, if it is determined that the selectedhypothetical soft-combined ACK bit stream represents a 1-bit ACK. 12.The apparatus of claim 10, wherein the decoder determines if theselected hypothetical soft-combined ACK bit stream represents a 2-bitACK, and decodes the selected hypothetical soft-combined ACK bit streamto determine the decoded ACK value, if it is determined that theselected hypothetical soft-combined ACK bit stream represents a 2-bitACK.
 13. The apparatus of claim 12, wherein the decoder decodes a twobit ACK value according to an equation expressed as (O₂ ^(ACK)=(O₀^(ACK)+O₁ ^(ACK))mod 2).
 14. The apparatus of claim 10, furthercomprising a memory that stores the plurality of hypotheticalsoft-combined ACK bit streams.
 15. The apparatus of claim 10, whereinthe subframe of symbols is received in an uplink transmission from theUE.
 16. The apparatus of claim 15, wherein the uplink transmissioncomprises an LTE uplink transmission.
 17. The apparatus of claim 15,wherein the uplink transmission is received over a physical uplinkshared channel (“PUSCH”).
 18. An apparatus, comprising: means forsoft-combining acknowledgement (ACK) bits received from a UE that arecontained in a received sub-frame of symbols, wherein the ACK bits aresoft-combined using a plurality of scrambling sequences to generate aplurality of hypothetical soft-combined ACK bit streams; means forreceiving a parameter that identifies a selected scrambling sequence tobe used; and means for decoding a selected hypothetical soft-combinedACK bit stream to generate a decoded ACK value, wherein the selectedhypothetical soft-combined ACK bit stream is selected from the pluralityof hypothetical soft-combined ACK bit streams based on the parameter.19. The apparatus of claim 18, wherein the means for decoding comprises:means for determining if the selected hypothetical soft-combined ACK bitstream represents a 1-bit ACK; and means for outputting the selectedhypothetical soft-combined ACK bit stream as the decoded ACK value, ifit is determined that the selected hypothetical soft-combined ACK bitstream represents a 1-bit ACK.
 20. The apparatus of claim 18, whereinthe means for decoding comprises: means for determining if the selectedhypothetical soft-combined ACK bit stream represents a 2-bit ACK; meansfor decoding the selected hypothetical soft-combined ACK bit stream todetermine the decoded ACK value, if it is determined that the selectedhypothetical soft-combined ACK bit stream represents a 2-bit ACK; andmeans for outputting the decoded ACK value.